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Due to the involvement of soil and stone in many projects over the years, in this case, people have created and applied different methods to stabilize, seal and protect the original soil. Geomembrane undoubtedly reflects the development of modern technology that transforms compacted ground into useful surfaces. Geomembranes can not only work below gravel and asphalt layers, but are also durable, weather-resistant, and can be flexibly used as waterproof tarps and custom covers. This article mainly describes the common applications of geosynthetic geomembranes, and you may find a suitable geomembrane type for your anti-seepage and waterproofing project.
Geomembrane is an impermeable sheet that can be used to protect, stabilize or seal exposed soil. Geomembranes are usually made of non-woven polymer materials, while other types of membranes cannot achieve the good effect of geomembranes because they cannot be directly installed on soil. Methods for producing geomembranes include calendering, coating and sheet extrusion. The main characteristics of most types of geomembranes, including flexibility, UV resistance, reinforcement grade and absolute polymer composition, vary widely among different products. Our geomembranes can be applied in many industries, such as waste management (landfills), water management (dams, tailings), agriculture, aquaculture, etc.
Nowadays, more and more geomembrane products can be applied to liners for any purpose. A large number of single-layer or copolymer membranes mixing two or even more polymer materials can provide the required characteristics. Geomembrane products are also produced in the form of geocomposites, in which two or more geosynthetic materials (geomembrane and geotextile) are mixed together or reinforced with fabric. Geomembranes usually add some additives, such as plasticizers, to extend the service life and durability of the product.
Most polymer materials used to produce geomembranes are thermoplastics, which are easier to weld and repair. The membranes commonly used in landfill anti-seepage and waterproofing projects are polyethylene because they have strong resistance to many chemicals.
Since geomembranes are mainly made of polymer materials with relatively large molecular weights, in this case, geomembranes have high density and strength, and the liner is also thick enough to maintain these characteristics. The installation process of geomembranes must be carried out under conditions of gradually increasing temperature, because waste biodegradation generates heat, causing the temperature to rise from 40°C to 70°C. Test performance data can only be obtained at elevated temperatures of at least 50°C. Once you are unsure whether the geomembrane is suitable for the waterproofing project of your landfill, dam, road or bridge, you need to follow the advice of experienced engineers or technicians.
According to different polymer materials, geomembranes can be mainly divided into PE geomembrane, PVC geomembrane, EVA geomembrane, TPO geomembrane, CPE geomembrane, CSPE geomembrane, EPDM geomembrane, etc. Considering practical applications in anti-seepage or waterproofing projects, PE geomembranes are used in projects such as reservoirs, dams, roads, etc. In addition, according to our own cases, composite geomembranes (also known as geocomposites) are more popular among our customers, and the service life of these geomembranes can be effectively extended.
Liquids and gases can permeate geomembranes through diffusion in the form of vapors or gases on a molecular scale. The permeability depends on the solubility of the liquid and the diffusivity of dissolved molecules in the geomembrane. The molecular concentration or partial pressure gradient on the geomembrane will become the driving force for the transmission direction and rate, while water head drives soil and clay in a completely different way.
Gas permeability varies greatly according to its nature and different types of geomembranes. Our continuous experiments demonstrate the permeability of geomembrane to organic aqueous solutions, simulating leachate containing small amounts of organic matter. Even if these organic compounds are present in low concentrations in the leachate, a large amount of organic compounds can permeate through the geomembrane.
Geomembranes are greatly affected by physical stress during transportation, installation and throughout their service life, some of which can be evaluated from the liner design step (such as the arrangement of anchors). Other stresses may occur due to temperature, such as expansion caused, or due to the possible presence of waste in landfills, so in the long run, the impact of chemical stress on the liner system should be considered first. These effects may take decades to manifest, including degradation of the base polymer, inevitable depolymerization, any form of waste assimilation, extraction of components (i.e., antioxidants), which can effectively determine the impact of leachate materials on the physical properties of geomembrane liners. Continuous experiments immersing liner materials in leachate chemicals at a temperature of 50°C may last for at least 4 months. More importantly, the comparison of HDPE geomembrane physical property measurement results is used to evaluate the compatibility of liners in contact with fluid waste over time.
Related reading: HDPE Geomembrane: Complete Guide to Types, Applications and Prices and the step-by-step geomembrane installation guide.
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